There are complications associated with catheter tip position being too low such as perforation of the heart, life threatening arrhythmias and clot formation. Complications related to catheter tip position being too high are also serious and include catheter dysfunction and vascular damage.
The more serious catheter complications such as right atrial thrombus or cardiac perforation and arrhythmias are related to tip position being too low, physically touching the posterior wall or floor of the right atrium. Because of that the FDA issued a statement recommending that the tip of catheter should not be in the heart. On the contrary, tip position too high can compromise catheter function as well as enhance fibrin sheathing and possibly subsequent central venous stenosis. For that reason many physicians prefer inserting the catheter tip into the right atrium. It seems that the catheter tip causes the complications associated with the low catheter placement and the most proximal openings are causing the complications associated with the catheter being placed too high.
Catheter complications are divided into three groups: Infection, thrombosis and fibrin sheathing. These complications are presenting while the catheter is still in the patient. They can present clinically or as catheter dysfunction. Delayed complications are central venous stenosis and occlusion as well as perforation, either of the central veins or the heart. Catheter function is also an important component of dialysis catheters and is influenced by the catheter position.
Side holes are thought to cause damage to the intima or lining of the adjacent vessel. The damage might be caused by the high pressures generated by the dialysis machine trying to aspirate large volumes of blood. This is happening at the proximal side holes of the arterial lumen of the catheter, which are located most proximally. This intimal damage might cause subsequent thrombosis and vascular stenosis.
The functional area of the catheter is between the tip and the most proximal opening. That opening is usually located several centimeters proximal to the tip. Currently, that most proximal opening can not be identified on imaging. The reason for that is that the most proximal opening is not marked and the whole catheter is radio opaque. The operator who wishes to insert the intravascular catheter accurately has no way of knowing where that most proximal opening is and where it is in relationship with the patient body or catheter tip. Also, the insertions of catheters are performed under fluoroscopy which provides at time poor image quality. In addition, some patients are overweight and this also contributes to poor image quality. The operator in these cases has a difficult time identifying the exact location and position of the catheter. The catheter embodiment disclosed in this invention will allow the physician to know exactly were the most proximal opening in the catheter is, where it is in relationship to the catheter tip and where it is to the anatomic markers in the patient's body.
Catheter positioning is usually done by locating the tip of the catheter on x ray or fluoroscopy. The intravascular catheter is usually radio opaque throughout its length. The operator identifies the catheter and catheter tip and positions it accordingly in the patient's body. The patient anatomy is identified on x ray or fluoroscopy. Specifically, the junction between the right atrium and superior vena cava is a common anatomical marker used for catheter placement. Tip position of the dialysis catheter is controversial and problematic. Some state that the tip should be in the superior vena cava, some advocate the right atrium and superior vena cava junction and some state that it should be in the right atrium. An often preferred tip position is one in which the tip of the catheter is at the upper part or middle of the right atrium. The present invention aims to make catheter position easier and more precise. The marker adjacent to the most proximal opening on the catheter will allow the operator to precisely and easily place that marker at the desired place, which can be the superior vena cava and right atrial junction. Since there are many types of catheters on the market and the proximal openings and tip design of these catheters vary considerably, this marker will allow better uniformity and accurate positioning, no matter what kind of catheter is used. Even though the catheter is radio opaque through its length, the radio opaque marker on top of that will allow identification of a particular location on the catheter which will make catheter insertion more precise.